Investigating the Mechanisms of Mindfulness-based Cognitive Therapy (MBCT)

There will be three groups in total.

• The first group will take 36 participants in remission from major depression (rMDD) through the 8 week MBCT program.
• A control group of 36 rMDD participants will not receive the intervention.
• A group of never depressed healthy control participants will also be recruited.

Research visits for participants not undergoing MBCT will be separated by an 8 week gap.

All participants will be seen before and after the 8 weeks for completion of neuropsychological assessments and questionnaires.

rMDD participants will be followed up over the following 12 months to identify any predictors of relapse.

Inclusion criteria

Participants with remitted depression (rMDD):

• At least two previous episodes of DSM-IV major depression in adulthood, diagnosed using the Mini International Neuropsychiatric Interview (M.I.N.I).
• Full or partial remission for at least three months with two depressive episodes within the last five years.
• A score of less than or equal to 12 on the Montgomery Asberg Depression Rating Scale (MADRS) mood assessment.
• If on medication, no recent or planned major changes

Healthy volunteers:

• In good psychological health screened with the M.I.N.I

All participants:

• in good physical health (to reduce risk of confounding physical health problems).
• sufficiently fluent in English to ensure valid understanding and completion of the tasks.
• minimum I.Q level of 80 to ensure sufficient understanding of the neurocognitive tasks administered.
• colour vision and acuity within normal/corrected to normal limits.

Exclusion criteria

• Any current mental health diagnosis (DSM-IV diagnosis including current major depression, bipolar disorder, psychosis, Obsessive Compulsive Disorder (OCD), substance abuse or dependence, eating disorders)
• Physical health or neurological disorders that might interfere with the interpretation of the tasks, including a history of significant head injury.
• In addition healthy volunteers will be without a history mental health disorders (DSM-IV)
• Current or previous experience of mindfulness-based treatments or extensive cognitive behavioural treatment, or planned participation in psychological treatments during the key time for the study (between pre and post visits).
• Planned major alteration in drug treatment for depression between pre and post visits.